Most aquatic insects emerge onto the surface of the water from below — they spend part of their lives in the water as a pupa or nymph, and then at some point they rise to the surface and emerge into their next lifestage. A nymph (a little wormy or buggy creature in the water) emerges into an adult (a winged, leggy critter that can walk on the water and fly away). Nymph flies like Hare's Ears and Pheasant Tails imitate the nymphal stage of the insect. Dry flies like BWOs and PMDs imitate the adult stage. You probably know most of this.

Emerger flies imitate the in-between stage, when the fly is in the act of emerging from its nymphal shuck, case, or whatever. Emerger imitations are not fished under the surface, and they're not fished on top of the water. Instead, they're fished in the surface film of the water. The reason they are effective is because fish like emerging aquatic insects — they are more vulnerable than other stages. A nymph might escape the fish by swimming, or be swept away from the fish by a chance current. An adult, obviously, can fly away or skitter across the surface. The emerging insect is stuck — it's trapped in the surface film, trying to get out onto the surface and into the air. If you've ever seen fish feeding just barely on the surface, so that they almost don't make a ring in the water, they're probably eating emergers.

You fish emergers the way you fish dry flies, but be aware that they sink a little — they don't sink down deep, but they don't exactly float on top, either. They kinda tough to see, sometimes. Some patterns have a flash parachute or some other marker to make them more visible, but in general you've just got to be on your toes. Cast them upstream of feeding trout and drift them over the fish — remember, the emerger is supposed to have come up from the bottom to the surface. The fish should not see the emerger land on the water.

A lot of ordinary dry fly patterns have an emerger variant. One of my favorites is the X-Caddis, which is an ordinary Elk Hair Caddis with some white dacron or some other dangly tail that represents the nymphal shuck. Sometimes the fish I go for just won't come after a fully hatched adult caddis on the surface — I guess maybe they get lazy. They want easier prey, a crippled or emerging caddis that is still struggling out of the water.

What EXACTLY Is An "emerger" Fly And How Do You Fish Them? is a post from: Fly Fishing Guide